Vehicle accessibility has been an ever present design challenge since modes of human transportation began using enclosed bodies. Countless closure mechanisms have been invented to solve the persistent problem. The factors influencing the solution that is available for a given vehicle include: exterior styling, interior usage, opening size, location of the opening on the vehicle body, and many others. In the case of side door openings on a typical multi-passenger vehicle, the generally used solution is to employ a single closure per opening that is separated from any adjacent closures by pillars. Each such closure has two single pivoting hinges placed at the front or rear end of the door to swingingly connect the door to the body, with both hinges supporting the weight of the door. A commonly used rule of thumb is to place the hinges with at least fifteen inches of separation between them to control gaps. Generally, a single latch is used at the opposite end of the door from the hinges to releasably hold the door in a closed position on the body.
Apart from the generally employed closure scheme, other means that have been developed include the double pivot door hinge of U.S. Pat. No. 5,632,065 and the double latching mechanism of U.S. Pat. No. 4,561,690. Both of these options have been used in the context of a double door closure scheme without a central opening pillar. That type of a system has been recognized as advantageous from an accessibility convenience standpoint. In spite of those references, the generally pursued option for closures on vehicles with multiple rows of seats has been to provide single doored openings with standard type hinges and to provide a means of manipulating the seats to aid in access. A reference showing that type of solution is U.S. Pat. No. 5,871,255.
Summarizing, the state of the art presently teaches that most vehicles include side doors that pivotably open on twin hinges that are connected to the vehicle body. Further, when multiple side doors are employed, all doors usually open in the same general direction. A well known exception is van type vehicles that commonly include sliding rear side doors to improve accessibility to multiple rows of rear seats. That system is much like the one used in the '690 Patent referenced above, (with a center pillar). Therefore, in the design process, if one where to stray from the common swinging door scheme, the prior art provides strong motivation for employing sliding rear doors. Venturing beyond that option remains unpredictable.